Salinity is recognized as a significant abiotic stressor that impairs crop growth and productivity. Elevated- soil and irrigation water salinity poses substantial ecological challenges for agriculture, particularly in semiarid and arid regions. High sodium (Na+) concentrations induce osmotic stress, leading to water deficits within plant cells. However, using nanoparticles can mitigate salt stress and enhance plant growth. This study investigates the effects of selenium nanoparticles on the physiobiochemical characteristics of Citrus limon L. seedlings under salt stress. Selenium nanoparticles act as both reducing and capping agents. Six-month-old lemon seedlings were subjected to varying salinity levels (100 mM and 200 mM NaCl) and treated with foliar applications of selenium nanoparticles at- 25 mg/L and 50 mg/L concentration. Most of the nano- structures were observed in the size range of 20-40 nm and anisotropic and irregular in shape. The results indicated that 200 mM NaCl significantly reduced the morphological and physiobiochemical parameters of the seedlings. However, a 50 mg/L concentration of SeNPs notably improved fresh and dry weights of roots and shoots and increased chlorophyll content. Biochemical attributes such as SOD, POD, CAT, APX, TSS, TFA, Proline, H2O2, and MDA were elevated under 200 mM NaCl, while NPK levels decreased. A concentration of 50 mg/L SeNPs was identified as optimal for enhancing the morphological and physiobiochemical parameters of C . limon seedlings under salt stress.

PurposeGrass pea (Lathyrus sativus L.) has significant nutritional value and broad-spectrum resistance properties. However, the neurotoxin beta-N-oxalyl-L-alpha, beta-diaminopropionic acid (beta-ODAP) in its seeds increases exponentially during drought stress, and overconsumption can lead to neurogenic hypoparalysis. Superabsorbent polymer (SAP) has the potential to improve soil physicochemical properties and alleviate plant drought stress, but the effects of different SAP concentrations on soil water availability, physiological traits, and beta-ODAP content of grass pea under drought conditions are unclear. The objective of this study was to elucidate the impact of SAP on the physiological and biochemical characteristics, as well as the beta-ODAP content, of grass pea under drought conditions.MethodsWe conducted potting experiments of natural drought with L. sativus cv. Wugong Yongshou (WGYS), L. sativus cv. Jingbian (JB), L. sativus cv. Aksu (AKS), and cultivated grass pea (ZP) materials with different SAP ratios (0.00%, 0.25%, 0.50%, 0.75%, 1.00%).ResultsThe research confirmed that the addition of 0.50% SAP had a positive effect on soil physicochemical properties and growth parameters of grass pea, including plant height, leaf area, leaf water potential, seed yield, and straw yield per plant; Following an eight-day cessation of irrigation, the transpiration rate (E), stomatal conductance (GH2O), intercellular CO2 concentration (Ci), and net photosynthetic rate (A) of the four grass pea leaves exhibited a notable optimization in comparison to the control without SAP; The levels of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), malondialdehyde (MDA), and beta-ODAP (leaves, seeds, and straw) of four grass pea plants treated with 0.50% SAP were significantly decreased.ConclusionSAP can improve soil water-holding capacity, leaf photosynthesis to alleviate oxidative damage caused by drought stress in grass pea, reduce beta-ODAP content, and promote low-toxicity and high-yield planting.

Sorghum [Sorghum bicolor (L.) Moench] grain yield is vulnerable to drought stress. Therefore, developing appropriate technologies to mitigate drought is essential. We hypothesize that inhibition of photosynthesis and reproductive success by drought in sorghum can be improved by enhanced osmolyte accumulation and antioxidant defence system by foliar application of nanoselenium. In this study, the ecotoxicity potential and the physiological basis of drought alleviation by nanoselenium were evaluated. Nanoselenium did not cause toxicity to soil, aquatic and terrestrial organisms up to 20 mg L-1.-1 . During drought, foliar application of nanoselenium at 20 mg L-1 reduced the transpiration rate (16 %) compared to water spray. The superoxide radical content (50 %), hydrogen peroxide content (35 %), and membrane damage (26 %) were reduced, indicating antioxidant activity was exerted by nanoselenium. In contrast, the leaf turgor potential (80 %), relative water content (17 %), reducing sugars (57 %), non-reducing sugars (11 %), and proline (35%) contents were increased by nanoselenium than water spray, indicating a higher tissue water content was maintained, which has increased the photosynthetic rate (26 %). Higher reproductive success in nanoselenium-sprayed plants under drought was associated with reproductive tissue morphology and an increased number of pollen grains attached to the stigma. Foliar application of nanoselenium at 20 mg L-1 increased seed-set percentage (21 %) and seed yield (26 %) under drought than control. A similar response was observed by foliar spray with sodium selenate. Overall, foliar application of nanoselenium at 20 mg L-1 improved the drought tolerance of sorghum by reducing the transpiration rate and increasing the antioxidant defense system. (c) 2024 SAAB. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Creeping bentgrass (Agrostis stolonifera) is an excellent cool-season turfgrass that is widely used in urban gardening, landscaping, and golf turf. Triennial field experiments from 2017 to 2019 were conducted to investigate effects of the foliar application of chitosan (CTS), gamma-aminobutyric acid (GABA), or sodium chloride (NaCl) on mitigating summer bentgrass decline (SBD) and exploring the CTS, GABA, or NaCl regulatory mechanism of tolerance to summer heat stress associated with changes in chlorophyll (Chl) loss and photosynthetic capacity, osmotic adjustment (OA), oxidative damage, and cell membrane stability. The findings demonstrated that persistent ambient high temperatures above 30 degrees C during the summer months of 2017, 2018, and 2019 significantly reduced the turf quality (TQ), Chl content, photochemical efficiency of PSII (Fv/Fm and PIABS), leaf relative water content, and osmotic potential (OP) but significantly increased electrolyte leakage (EL) and the accumulations of free proline, water-soluble carbohydrate (WSC), hydrogen peroxide (H2O2), and malondialdehyde (MDA). The foliar application of CTS, GABA, or NaCl could significantly alleviate SBD, as reflected by improved TQ and delayed Chl loss during hot summer months. Heat-induced declines in Fv/Fm, PIABS, the net photosynthetic rate (Pn), the transpiration rate (Tr), and water use efficiency (WUE) could be significantly mitigated by the exogenous application of CTS, GABA, or NaCl. In addition, the foliar application of CTS, GABA, or NaCl also significantly improved the accumulations of free proline and WSC but reduced the EL, OP, and H2O2 content and the MDA content in leaves of creeping bentgrass in favor of water and redox homeostasis in summer. Based on the comprehensive evaluation of the subordinate function value analysis (SFVA), the CTS had the best effect on the mitigation of SBD, followed by GABA and NaCl in 2017, 2018, and 2019. The current study indicates that the foliar application of an appropriate dose of GABA, CTS, or NaCl provides a cost-effective strategy for mitigating SBD.

Uncertainties about the ecophysiological response of plants to elevated temperature limit our ability to predict the impact of climate change on plants, especially in tropical and subtropical forests. One important source of the uncertainties is that the vast majority of warming studies manipulated only aboveground or only belowground temperature when in the real word warming takes place both aboveground and belowground. We used a full factorial design of air warming and soil warming with four temperature treatments: (1) unwarmed, (2) soil warming, (3) air warming, (4) soil plus air warming to explore the effects of warming on ecophysical processes/ characteristics of leaves and fine roots of Chinese-fir saplings. We measured photosynthesis, concentrations of oxidant substances, activity of antioxidant enzymes, and osmoregulatory substances in leaves and fine roots. We found that the soil warming increased photosynthetic rate by 68.9%, but air warming and soil plus air warming treatments did not. The concentrations of oxidant compounds, superoxide anion (O2- ), hydrogen peroxide (H2O2) and malondialdehyde (MDA) were higher in leaves than in fine roots under all treatments, possibly due to their differences in the degree of oxidative damage. Soil warming increased leaf catalase (CAT) activity by 58.5%, soil warming and air warming increased leaf peroxidase (POD) activity by 31% and 42.3%, respectively, and soil plus air warming increased leaf ascorbic acid peroxidase (APX) activity by 31%. These increases in antioxidant enzyme concentrations indicated that warming activated leaf antioxidant systems. The CAT activity was lower in leaves than in fine roots, while the POD activity and concentrations of osmoregulatory substances were higher in leaves than in fine roots across all treatments. Our study clearly illustrated that different warming treatments (aboveground and belowground) had different effects on plant growth and physiological processes. The differences in oxidant compounds and activities of antioxidant enzymes between leaves and fine roots indicated that warming affect different organs differently. This study provides insights into how climate warming may affect important physiological and biochemical processes in subtropical forests.